This invention relates to torsional dampers and more particularly to torsional dampers for torque converter clutches.
Clutch dampers which reduce torsional vibrations brought about by engine torque spikes are well known. Dampers for torque converter clutches have generally been spring-type dampers. In these dampers, springs are utilized to permit relative motion between the input and output members of the clutch. The energy stored in the springs is either returned to the output when the torque spike decreases or partially given up to a friction damper in parallel with the springs.
A viscous clutch in series with a friction clutch has also been used. The viscous clutch does not pass the torque spikes or torsional vibrations, similar to a fluid coupling, so that the operator does not feel the torsional vibrations downstream of the torque converter when the clutch is engaged.
Another device for reducing the input torsional vibrations to a transmission is a slipping clutch. The slipping clutch is utilized in the same space as a fully engaged torque converter clutch. The slipping clutch is controlled by apply and release pressures so that complete engagement is not reached. Because of the slipping interface between the engine output and the clutch input, the torsional vibrations are not transmitted to the clutch member.